A clinical trial will test (1) an intervention derived from self- determination theory and applied to smoking cessation, diet improvement, or both, as compared to usual care and (2) the self-determination model of the processes that underlie maintained health-behavior change. All participants will be adult cigarette smokers, stratified in terms of whether their LDL cholesterol is or is not at NCEP-recommended goal (which varies as a function of health and risk status). Those at goal will be randomly assigned either to a self-determination intervention or to usual care for smoking cessation. Those not at goal will be randomly assigned to one of four conditions created by the factorial cross of a self-determination intervention versus usual cre for reduction in dietary fat intake. Thus, we will test the effects of the self- determination-theory intervention for smoking cessation, diet improvement, and both. Further, using Structural Equation Modeling we will test the fit of the self-determination model to the data both within the intervention groups and within the usual-care groups. The 6-month intervention for smoking cessation and diet improvement involves a behavior-change counselor working with participants to encourage and support change of one or both of these two risk behaviors (depending on experimental condition). The counselor will employ self- determination theory principles, which include eliciting and acknowledging the patients' perspectives and values, providing choices and relevant information, promoting perceived competence, and minimizing pressure to change. The intervention, which is consistent with and builds upon the AHCPR guidelines for smoking cessation and the NCEP guidelines for lowering cholesterol was designed to operationalize the positions of self-determination theory so its applicability to change of these two health-risk behaviors could be tested. Outcomes assessed at 6 and 18 months include 7-day point prevalence smoking cessation (validated by serum cotinine), reduction in percentage of calories from rat assessed by 24 dietary recalls, and improvement in measured and calculated LDL cholesterol.